Who defended the Aztecs?

The Aztecs were primarily defended by their own military forces, which were well-organized and comprised various warrior classes. They also had alliances with neighboring city-states, such as Tlacopan and Texcoco, which formed the Triple Alliance that bolstered their defenses. Additionally, the Aztecs employed tactics such as fortifications and strategic warfare to protect their empire from invaders. However, they ultimately faced significant challenges from Spanish conquistadors led by Hernán Cortés in the early 16th century.